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June 11, 2014

Interpretation of Hemoglobin A1c Values

Author Affiliations
  • 1Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland
  • 2Department of Clinical Biochemistry, Norfolk and Norwich University Hospital, and Norwich Medical School, Norwich, United Kingdom
JAMA. 2014;311(22):2271-2272. doi:10.1001/jama.2014.6342

Since better glucose control reduces microvascular complications in patients with diabetes, reliable evaluation of diabetes control is essential. Hemoglobin A1c (HbA1c) values reflect average glucose over approximately 120 days (the average erythrocyte lifespan) and are a better assessment of glucose control than blood glucose measurement, which provides information at only one point of time. Although HbA1c is universally accepted as a means for monitoring diabetes control, its measurement is challenging. Concerns have been expressed about deficiencies of HbA1c analysis—most notably, lack of accuracy and inability to use HbA1c in subsets of individuals (eg, patients with hemolytic anemia or acute blood loss). This Viewpoint addresses some important considerations relevant to laboratory determination of HbA1c.